Heat pumps have become very popular today due to the increasing interest in green energy.

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Renewable energy sources are an excellent alternative to traditional coal energy, which is why an increasing number of countries decide to change their energy economy to a greener one. Despite the popularity of heat pumps, few people actually know how they work.

The history of heat pump: where did this groundbreaking invention come from?

It might seem that the heat pump was invented and constructed within the last two decades. It turns out that the history of the heat pump dates back to the 19th century. In Frenchman Nicolas Carnot published the first principles of heat pump operation. At that time, it was just a theory supported by a few experiments, so it took more than 100 years to create a fully operational heat pump. The first big heat pump systems were put into operation in Zurich to heat the congress building, the town hall, offices and an indoor swimming pool.

The first ground source heat pump was activated in the United States in . It is worth noting that this pump was installed in the house of its designer, Robert C. Webber, in Indianapolis. The device was equipped with a compressor having a nominal power of 2 kW.

Heat pump technology has been developed over decades, which is why modern technological solutions make current heat pumps incredibly efficient and effective.

Main types of heat pumps

Heat pumps are classified according to the so-called lower heat source. Hence, we divide them into ground, water and air source devices. Often, we can also see heat pumps classified as air-water, water-water and glycol/brine-water pumps. Air-to-water heat pumps are the most popular type at this time. They do not require additional expenditure on the collection of heat from the lower source.

Heat pump operation depending on the type of lower source

At this point, we should point out that the heat pump operation is determined by the type of the lower heat source. Modern heat pumps come with three basic types of the so-called lower source: air, water and ground, meaning that heat pumps are divided into:

• An air source heat pump uses a fan that allows air to flow through the heat exchanger. As we already mentioned, the heat is then received through the refrigerant. Remember that there are two types of air source heat pump – monobloc and split pumps.
  
  In a monobloc pump, the refrigerant is condensed in the outdoor unit. It then transfers the heat to the heating water or glycol. Then water or glycol is pumped to the hydraulic module in the house and further distributed in the system. In the case of a monobloc pump, the entire refrigeration system is enclosed in a unit outside the building. KOSPEL offers a monobloc heat pump set. The other type – split air source heat pump – differs from the monobloc, as its outdoor unit is connected to the internal hydraulic module through tubes with a refrigerant.
• A ground source heat pump is characterised by the most stable source of heat. It is worth mentioning that it is also the most expensive investment option. A vertical borehole or a serpentine-shaped heat exchanger placed in the ground below the freezing level is filled with glycol. The ground is heated by sun rays, allowing the heat to be used for operating the pump, while boreholes utilise geothermal heat. This type of heat pumps is limited only to the indoor unit containing the entire cooling circuit, which consists of the primary exchanger receiving heat from an external source and the secondary exchanger for transferring the heat to the heating system.
• A water source heat pump operates very similarly to a ground source pump. The difference lies in the source of heat, which is water from a reservoir (lake or river) or from groundwater. We should emphasize, however, that water source heat pumps are the least common type of pumps because of the specific heat source conditions. A water source heat pump requires a body of water, such as a lake, near the house.

Air source heat pumps remain the most popular type due to their simple installation and the great availability of air as the heat source.

Heat pump operation and design

We know the history of heat pump, so now let’s find out how it works. Surprisingly, heat pumps are based on the same principle of operation as refrigerators. As strange as it sounds, a refrigerator and a heat pump work in a similar way – refrigerators take heat from inside them and transfer them outside (which is why the back of the refrigerator is always warm). Heat pumps extract heat from the outdoor air, ground or water and transfer it into our house.

The key to the heat pump operation is the refrigerant. Liquid is evaporated at a specific temperature, which can be clearly seen in water, for example: water for tea must reach 100°C to boil in the kettle. It is then easy to get burned by the vapour produced by boiling water. It happens to everyone, and the cause is the fact that water gives off heat when condensing as vapour.

It is worth noting that we just need to find a refrigerant that evaporates at a temperature lower than 100°C to achieve the same effect of heat absorption. Some refrigerants are able to evaporate at sub-zero temperatures, so we can gain heat even from air that is close to zero temperature (or even below).

Why use a heat pump – advantages

A heat pump is a great alternative to traditional heating of house and domestic hot water. It should be pointed out that heat pumps are perfect in combination with a photovoltaic system. The combination of photovoltaics with a heat pump provides environmentally-friendly and economical heating at home, which is why this solution is so popular today.

The main advantage of heat pump is very comfortable and convenient use. It is worth noting that the heat pump is a renewable energy source, so it gives you self-sufficiency when combined with PV. Exchangers with a large coil surface are especially recommended for heat pumps. Your heat pump will also need a buffer tank for smooth, safe and cost-effective operation.

There are many benefits of using heat pumps. These devices have a large impact on reducing energy bills, they do not emit pollutants and are completely safe to use. Due to their design and technology, heat pumps are practically maintenance-free.

Thanks to quiet and clean operation, a heat pump can usually be installed at any desired location. Heat pumps perfectly play their role in houses as well as in commercial/public utility buildings.

Heat pump - what is it and how does it work?

Chiller is a refrigeration machine for cooling liquids, which is widely used in all industries where there is a need to remove excess heat. Despite this, the variability of chiller options is quite wide. They can be equipped with a hydraulic module, a freecooling option, and can have increased efficiency or reduced noise. But today we will look at one of the most popular options for chillers – a heat pump. So what is this equipment and how does it work?

A heat pump is a device for obtaining thermal energy from the environment and using it for heating and water heating. Such pumps successfully heat and provide hot water to entire cities. The popularity of the equipment and the growth in demand for it are associated with the cost-effectiveness of the device: spending 1 kW of electricity, the heat pump produces 3-5 kW of thermal energy and.

If you are looking for more details, kindly visit Heat Pump with Hydraulic Module.

The operating principle of a heat pump, like a chiller, is based on heat transfer. If the chiller transfers heat from the consumer to the street, the heat pump, on the contrary, transfers heat from the street to the consumer, thus changing places of the condenser and evaporator.

In order to change the “heating” to “cooling” mode, a 4-way valve is used, switching the direction of freon flow.

The efficiency of a heat pump confuses many people, because if you calculate it, it is fundamentally more than 1 00%. However, such calculations are simply incorrect and do not take into account the energy source other than the electricity consumed. This source is usually air. Electricity in the device is not spent directly on heating, but only on “concentrating” the energy of a low-grade heat source, as a rule, providing energy for the operation of the compressor. That is, the heat pump has two energy sources – electricity and a source of low-grade heat, and the calculations do not take into account the second source, and values greater than one are erroneously obtained.

A more correct coefficient for characterizing the productivity of a heat pump was taken to be the coefficient COP – transformation coefficient (or productivity coefficient) . The higher the number, the more efficient the heat pump is. So, if the technical documentation says that the efficiency is 400%, then this should be interpreted as: COP of this equipment is equal to 4. COP is calculated using the formula:

COP=T2/(T2-T1)

where:
T1—- temperature of the natural source (air)
T2—- temperature of the coolant

The idea of a heat pump was developed back in by the eminent British physicist Lord Kelvin. However, practical application of the heat pump came about in the s when inventor Robert Weber was experimenting with refrigeration equipment. Weber accidentally touched a hot pipe of the condenser and realized that heat was simply being expelled outside. The inventor pondered how to utilize this heat and decided to place the pipe in a boiler to heat water. As a result, Weber provided his family with a huge amount of hot water. Moreover, part of the heat from the heated water was released into the air. This prompted the scientist to think that one heat source could simultaneously heat water and air, so Weber improved his invention and began to run hot water through a spiral heat exchanger, and with the help of a small fan, distribute heat throughout the house for heating purposes.

Currently, more and more attention is being given to the chiller-heat pump, the so-called four-pipe system with air-cooled condenser. Such a chiller is a device designed for simultaneous cooling and heating of the heat transfer medium. This unit can provide chilled and hot water year-round, as well as supply warm water for sanitary needs. Thanks to this, the facility can operate without additional costs, ensuring significant electricity savings.

The four-pipe chiller-heat pump is well suited to meet the needs of manufacturing plants, medical institutions, logistics companies, museums, vegetable stores, and other facilities where strictly defined temperature conditions need to be maintained in various premises.

The four-pipe chiller-heat pump can be operated in one of three modes:
1. Cooling only;
2. Heating only;
3. Cooling and heating.
It can also automatically adjust the cooling and heating power of water depending on environmental conditions and user settings, and quickly switch from one operating mode to another.

The operating temperature range of modern heat pumps is within the following limits:

• In cooling mode – at outdoor temperatures from 0°C to 45°C they can provide a coolant temperature from 3 °C to 20°C. However, many manufacturers produce models that allow the operation of equipment to produce coolant at sub-zero temperatures down to -10 °C, as well as operation at ambient temperatures down to -15 °C or even lower. In this case, it is necessary to use non-freezing mixtures as a coolant, such as propylene glycol, ethylene glycol, etc.
• In heating mode – at outside temperatures down to -15°C, they provide hot water with temperatures up to 60 °C, however, there are also models that can operate at air temperatures down to -25°C.

To summarize, the chiller heat pump can operate at outdoor temperatures in winter up to -25 °C, in summer up to 48 °C. The water temperature can be up to 60 °C in heating mode and up to 10 °C in cooling mode. However, it must be said that already at an ambient temperature of -15 ° C , an increase in energy consumption and a decrease in the performance of the heat pump begins.

Modern chiller-heat pumps are manufactured with both plate and shell-and-tube heat exchangers. For high-power equipment, screw compressors are used, because the performance of the latter can be smoothly adjusted in the range from 100% to 25%, which ensures more accurate and smooth maintenance of the required temperature. At the same time, for equipment of medium and low power, scroll compressors are used, and to regulate their performance, so-called inverters or frequency converters are used. Also, for both types of compressors, in order to ensure stable operation of the system, at negative ambient temperatures, the technology of vapor-liquid injection (injection) of freon into the compressor is used.

If it is not yet very cold outside, the evaporator produces a sufficient amount of steam. It enters the compressor mainly through the low pressure line, and the injection line is almost not involved. In this mode, the heat pump operates at maximum efficiency, absorbing heat from the outside air. As the outside temperature decreases, the amount of steam in this line decreases and the control system increases the refrigerant flow in the injection circuit, maintaining the required gas flow through the compressor.

Evroprom has a wide range of heat pump chillers, such as SYSTEMAIR SYSAQUA 90 with a power of 91.4/88 kW, PANASONIC ECOI-W AQUA-Z 2C 170CH with 170/187 kW power and hydronic module, or AERMEC NRB XHA with 969/ kW power, hydronic module and increased efficiency function. In addition, we have many used chillers, which you can see on our website!

❗️ Evroprom – your trusted friend in matters of refrigeration equipment. We will choose the best cooling solution for your needs.

Contact us to discuss your requirements of Local Heat Pump Service and Support. Our experienced sales team can help you identify the options that best suit your needs.